For some in ANY abusive relationship or simply unhappy, a fear of the unknown and that what is known is better than the unknown and unfamiliar. I think I felt that way in my marriage and also felt a duty to keep on going. Fortunately my wife cheated on me and ended that ;-) There may also be a certain amount of brainwashing. Some people get so beaten down they cannot help themselves. Why it helps if others are willing to try to help them help themselves.